Tasty and efficient preparation of popcorn requires, as well as the pop corn kernels, high heat and cooking oil. The cooking oil functions to coat the corn kernels for insuring even distribution of heat throughout the kernel. The popping apparatus must provide at least these three basic necessities. It must further provide for efficient corn loading and simple delivery of popped corn. Additionally, it is highly desirable that the popping apparatus permit easy and rapid periodic cleaning, be reliable, and allow simple maintenance in case of faults.
Conventional popping apparatus uses thin steel popping bowls. Even though the bowls may be copper plated for increased heat conductivity, they are subject to uneven temperatures, with hot spots forming near heating elements. This results not only in uneven popping but possible burning of the corn kernels. An even temperature produces more flavorful popcorn. Further, the hot bowl surfaces are exposed externally. Since temperatures up to 450.degree. F. are routinely used for corn popping, considerable heat loss and inefficient energy use results. Also the hot surfaces place the operator of the popping apparatus at risk of serious burns. Even momentary contact with a metal bowl at such a temperature can be dangerous.
The cooking oil needed for corn popping must be introduced into the popping bowl. Cooking oil distribution is a particular problem with prior devices. The oil is generally preheated to nearly popping temperature and then conventionally conducted through an inverted J-shaped tube and allowed to fall into the popping bowl. Since popping bowls generally must be covered to contain the energetically popping corn, an oil passage through the lid must be provided. This conventional design, involving hot oil falling towards a restricted passage through the popping bowl lid, first, exposes the hot oil to air. This is undesirable as it leads to various types of avoidable oil contamination. Second, if even slight misalignment of the oil tube and the oil passage in the lid occurs, hot oil will spill down the sides of the heated bowl. Since bowls are conventionally electrically heated, spilled oil may be a fire hazard. In any case, the hot oil will oxidize on the bowl to create an unsightly residue difficult to clean. Thus, such spillage is both a possible fire safety hazard and an immediate cleaning problem. Access to these surfaces for routine daily cleaning of these surfaces is difficult. Cleaning requires extra operator attention.
Further, a popping apparatus must meet certain mechanical requirements. This cooking bowl must be easily accessible for kernel loading. Popped corn must be externally delivered during popping and between loads of corn. Conventionally, popping devices provide a hinged lid for loading and overflow during popping along with a pivoting capability for final emptying of the entire popping bowl. A handle to manually pivot the popping bowl is thus required. Typically, a short handle attached directly to the uninsulated, hot popping bowl is provided. During routine operation, the operator must bring a hand near the hot bowl surfaces and grasp a grip attached to a short, hot handle. If the operator's hand slips onto the metal portions of the apparatus, burns are likely. This increases operator risk.
Further, the bowl is generally held in an operative position by a return spring. The required pivoting motion of bowl often is not smooth, the bowl returning to its operative position with extra force, where it will often bounce against its supports. This bounce and vibration makes operation more difficult. It can also mar or even damage the apparatus over time.
Corn poppers of this intended use universally generate the necessary high heat by electric heating elements. The heating elements required are often rated from 5 up to 10 KW. These elements draw high currents. Conventionally, prior devices included mechanical contacts in the high current path to facilitate pivoting of the kettle. These contacts are less reliable than current paths not requiring mechanical interruption. Also, conventional heater control circuitry uses thermostats. These are electromechanical parts also prone to failure. Finally, even the heating elements and their passive contacts, repeatedly subject to high heat and thermal stresses, will fail. These electromechanical failures must be minimized to the maximum possible extent to increase popping device availability.
When they occur, these and other types of failures must be easily and rapidly repaired. Prior popping device assemblies generally involve many washers, spacers, and other mechanical parts. Return springs and elaborate pivot mechanisms add to the complexity of the device. This mechanical complexity makes prior devices difficult to disassemble and reassemble, often beyond the abilities of the average operator staff. Routine repair may thus require special personnel, and results in unnecessary downtime.
Prior corn popping devices have inadequately addressed these problems. The present invention provides coordinated solutions to the problems of a corn popper of increased efficiency, safety, reliability, and maintainability.